Refrigerating apparatus



1943- 1.. A. PHILIPP 2,325,706

REFRIGERATING APPARATUS Filed April 12, 1941 2 Sheets-Sheet 1 INVENTOR.Lqwezncr. fl. Pmurr aw-9km) Patented Aug. 3, 1943 REFRIGERATINGAPPARATUS Lawrence A. Philipp, Detroit, Mich., assignor toNash-Kelvinator Corporation, Detroit, Mich., a

corporation of Maryland Application April 12, 1941, Serial No. 388,253

3 Claims.

This invention relates to refrigerating apparatus, and, moreparticularly, to refrigerant evaporators.

One of the objects of my invention is to provide an improved refrigerantevaporator for freezing substances and for cooling the circulating airwithin a refrigerator cabinet.

Another object of my invention is to provide an improved refrigerantevaporating unit which comprises a non-flooded refrigerant evaporatingsection and a flooded refrigerant evaporating section arranged togetherin the form of a U and connected to each other by two spaced apartrefrigerant manifolds having restricted passages therebetween forconducting refrigerant from the non-flooded section to the floodedsection in a uniform and evenly distributed flow.

Another object of my invention is to provide an improvedrefrigerantevaporator which comprises a serpentine refrigerant evaporating conduitconnected in series to a plurality of parallel refrigerant evaporatingpassages by means of two spaced apart refrigerant manifolds havingrestricted passages therebetween which serve to conduct refrigerant fromthe serpentine conduit to the refrigerant passages, said serpentineconduit and refrigerant passages being arranged in U-shaped conformationto enclose a freezing zone and to present surfaces for cooling thecirculating air within a refrigerator cabinet.

Another object of my invention is to provide an'improved refrigerantevaporator which comprises two sheets of metal formed to provide aplurality of refrigerant evaporating passages arranged in parallel flowrelationship and having an outlet header and an inlet refrigerantdistributing manifold, and a serpentine refrigerant evaporating conduitconnected to the distributing manifold by means of restricted passageswhereby refrigerant from the serpentine conduit is injected into thedistributing manifold at a number of points for uniform distributionthroughout the refrigerant passages.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings, wherein a preferred form of th present invention is clearlyshown.

Fig. 1 is a perspective view of my improved evaporator in schematicarrangement with a refrigerating system;

Fig. 2 is a perspective view of the same evaporator shown in Fig. 1 withthe opposite side in the foreground;

Fig. 3 is a transverse cross-sectional view of the evaporator taken online 3-3 of Fig. 1;

Fig. 4 is a plan view of the sheet metal portions of the evaporatorshown in Fig. 1 prior to bending;

Fig. 5 is a plan view of the sheet metal portions of a modifiedembodiment of my evaporator prior to bending;

Fig. 6 is a longitudinal View in cross section of the modifiedevaporator taken along line 66 of Fig. 5;

Fig. 7 is a transverse cross-sectional view of the modified evaporatorshown in Fig. 5 after bending taken along line of Fig. 5 with arefrigerated shelf included;

Fig. 8 is a longitudinal view in cross-section of another modificationof my evaporator be-' fore bending; and

. Fig. 9 is an end view in elevation of the modified evaporator shown inFig. 8 after bending into final form and with a refrigerated shelfincluded.

In accordance with my invention, I have provided an improved refrigerantevaporating unit for freezing purposes and for cooling the circulatingair within a refrigerator cabinet. This unit comprises two sheets ofmetal of U-shaped conformation formed to provide a non-floodedrefrigerant evaporating section and a flooded refrigerant evaporatingsection. These two sections are connected to each other by two spacedapart refrigerant manifolds having at spaced points a plurality ofrestricted passages therebetween. The non-flooded section preferablyconsists of a serpentine conduit or passage arranged in an L-shapedconformation and connected to one of the refrigerant manifolds while theflooded section preferably consists of a plurality of parallelrefrigerant passages extending between an outlet header and the other ofthe refrigerant manifolds and also arranged in an L-shaped conformation.Refrigerant is supplied to the non-flooded section first and is thenintroduced into the flooded section by means of the two manifoldsconnected by the restricted passages. By this arrangement, a uniform andbalanced distribution of refrigerant is obtained throughout both theflooded and the non-flooded sections so that a uniform freezingtemperature may be maintained within the evaporator while an air-coolingsurface of substantially uniform temperature is presented to thecirculating air within the refrigerator cabinet.

Referring to the drawings, there is illustrated a refrigeratingapparatus Ill comprising a compressor-condenser unit II and anevaporator l2 which is adapted to be positioned within an enclosedcompartment that is to be cooled. The compressor-condenser unit llincludes a motorcompressor unit l4 and a condenser IS. A conduit l6connects the discharge side of the compressor to the condenser I and asmall diameter or capillary tube l1 connects the discharge side of thecondenser with the evaporator l2 A conduit connects the outlet side ofthe evaporator l2 with the suction side of the compressor unit l4. Aportion of the length of the conduits I! and 20 are in thermal or heatexchange relationship as at 22. Suitable controls, not shown, may beemployed for controlling the cycle of operations of the motor-compressorunit M which during the onphase withdraws refrigerant vapor from theevaporator I2 through the conduit 20 into the compressor where it iscompressed and then discharged through conduit !6 into condenser i5 tobe cooled, liquefied and returned through conduit I! to the evaporator.The diameter of the conduit I1 is such as to meter the flow of liquidrefrigerant therethrough in predetermined quan titles. The refrigerantin conduit I1 is further cooled by thermal exchange with the returningrefrigerant vapor in conduit 20.

The evaporator l2 comprises two sheets: of metal 24 and 25 bent in theform of a U and nested one within the other, the outer sheet 24 beingembossed to form refrigerant circulating passages when Welded orsoldered to the inner sheet 25. Embossed in the outer sheet is aserpentine refrigerant conveying conduit 26 which includes a pluralityof convolutions 28 running up and down one side of the evaporator andover a portion of the bottom. Embossed in the other side of theevaporator is a plurality of parallel refrigerant passages 30 whichsubstantially cover the side of the evaporator and the remaining portionof the bottom. These passages are provided at their upper ends with anoutlet header 32 formed by embossing both the inner and outer sheets andat the lower end with a distributing manifold 34 formed in the outersheet 24. Between the .lowerends of the serpentine conduit 26- and thedistributing manifold 34 there is embossed in the outer sheet arefrigerant receiving manifold 36 in spaced relationship to thedistributing manifold. Between this manifold 36 and the distributingmanifold 34 a plurality of restricted passages 38 are provided forconveying refrigerant from the receiving manifold to the distributingmanifold. These restricted passages are preferably spaced at regularintervals so that refrigerant from the receiving manifold 36 is injecteduniformly throughout the length of the I manner as by welding orsoldering to the under "Side of the shelf 43. This conduit is directlyconnected at one end to the small diameter tube I! at the rear of theshelf and at the other end by means of a short conduit 48 to theserpentine conduit 26. Brackets 50 are provided at the top of theevaporator for supporting it within the. cooling compartment of therefrigerator.

In operation, my improved evaporator provides a uniform and effectivedistribution of liquid refrigerant on two sides and the bottom of thenested U-shaped sheets of metal. Refrigerant is admitted to theserpentine conduit 26 from the shelf conduit 46. If first circulatespreferably to the front of the evaporator and then up and down one sideof the evaporator and across a portion of the bottom to provide uniformeffective cooling throughout that side and bottom. The liquidrefrigerant and refrigerant vapor enter the receiving manifold 36,wherebecause of the restricted passages 38 a pack pressure is built up. As aresult refrigerant from the receiving manifold enters the distributingmanifold 34 in substantially equal amounts through the restrictedpassages 38 at regularly spaced intervals throughout the distributingmanifold. From the distributing manifold the refrigerant is distributedto the several refrigerant passages 30 in substantially uniform andequal quantities, thereby producing a uniform upward flow of refrigerantthrough all the parallel refrigerant passages. Because of the number ofpassages and because of the uniform distribution of refrigerantthroughout the passages, an eifective and uniform heat transfer surfaceis provided. The refrigerant circulates into the outlet header 32 fromwhich evaporated refrigerant is returned to the compressor-condenserunit by the suction conduit 20. Thus it will be seen that I haveprovided a refrigerant evaporator comprising two sheets of metal formedto provide a single serpentine passage connected in series relationshipwith a plurality of parallel refrigerant passages in such mannerthat'refrigerant from the serpentine passage is circulated concurrentlyand uniformly up through the parallel passages to provide effective heattransfer surfaces of sub stantially the same temperature.

In Figs. 5, 6 and 7 there is shown a modification of my improvedevaporator. It comprises two sheets of metal, an inner sheet 50 and anouter sheet 52. The outer sheet 52 is embossed to form refrigerantcirculating passages when secured as by soldering or Welding to theinner sheet 56. The sheets are preferably bent into U-shapedconformation to provide a freezing compartment and an air coolingsurface. In this modification, the outer sheet of metal is somewhatshorter than the inner sheet so that the inner sheet extends beyond theouter sheet on one side of the evaporator as at 54. This portion of theinner sheet is embossed as at 56 to give added rigidity. The outer sheetis embossed to provide a serpentine passage 56 which opens into arefrigerant receiving manifold 60. The rest of the outer sheet isembossed to provide a header 62, an outlet manifold 64, an inletdistributing manifold 66 and parallel refrigerant passages 66 runningbetween the inlet manifold 66 and the outlet manifold 64. Therefrigerant receiving manifold 60 is connected to the refrigerantdistributing manifold 66 as in the preferred embodiment by means ofrestricted passages 10 spaced at regular intervals along thedistributing manifold. The outlet manifold 64 in this embodiment ispreferably spaced from the outlet header 62 so that when the sheet metalportions are bent in U-shaped conformation this outlet manifold lies inthe same horizontal plane as the uppermost part of the serpentineconduit 58. i This outlet manifold is connected to the outlet header 62by means of conduits I2 and 14. The space in the outer sheet 52 betweenthe manifold and th header is preferably embossed to give added rigiditythere-- between. Shelves 15 and 16 are provided within the evaporatorfor supporting receptacles of substances to be frozen. A serpentineconduit 11 serves to refrigerate shelf 16. In this modification a morelimited heat transfer surface is provided by the above arrangement ofthe refrigerant circulating passages. Otherwise the operation is thesame as that of the preferred embodiment. Refrigerant is admitted fromthe refrigerated shelf 16 into the serpentine conduit 58 which extendsonly part way up one side of theevaporator and across a small portion ofthe bottom. Refrigerant leaving the serpentine conduit is injected fromthe receiving manifold 60 into the distributing manifold 66 of theparallel passages 68 which extend across the remaining portion of thebottom of the evaporator and part way up the other side to the outletmanifold 64. Evaporated refrigerant and whatever unevaporatedrefrigerant there may be is circulated to the header 62 from which theevaporated refrigerant is conducted back to the compressor unit. Thus itwill be seen that a substantial part of both sides of the evaporator isleft unrefrigerated thereby providing an evaporator which in conjunctionwith the refrigerated shelf is adapted to maintain a large freezing zonewhile presenting only a small air cooling surface. Such an evaporator isparticularly adapted to be used for cooling a compartment in conjunctionwith another cooling unit such as a secondary evaporator. I

In Figs. 8 and 9 there is shown another modification of my improvedevaporator. In this modification which corresponds substantially withthat illustrated in Figs. 5, 6 and 7, an outlet header 80 is providedwhich instead of being located as in the modification shown in Figs. 5,6 and 7, is placed where the outlet manifold 64 is located and theoutlet manifold 64 itself is eliminated. Otherwise the two evaporatorscorrespond and corresponding numbers indicate corresponding parts.

Although only a preferred form of the invention has been illustrated,and that form described in detail, it will be apparent to those skilledin the art that various modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

I claim:

1. A U-shaped refrigerant evaporator comprising two sheets of metalformed to provide a serpentine refrigerant conduit in one side and aportion of the bottom thereof, a plurality of refrigerant passagesextending up the other side and across the remaining portion of thebottom, said refrigerant passages being provided at their upper endswith an outlet header and at their lower ends with an inlet manifold,and restricted passages for injecting refrigerant from said serpentineconduit into said inlet manifold.

2. A refrigerant evaporating unit comprising.

an L-shaped non-flooded refrigerant evaporating section, an L-shapedflooded refrigerant evaporating section, two spaced apart refrigerantmanifolds, one in direct communication with said non-flooded section andthe other in direct communication with said flooded section, andinjecting means directly connecting between said manifolds forconducting refrigerant from said non-flooded section to said floodedsection.

3. A refrigerant evaporating unit of box-like conformation comprising anon-flooded serpentine refrigerant passage for cooling the top wall, anL-shaped non-flooded refrigerant evaporating section for cooling thelower portion of a side wall and a portion of the bottom wall, anL-shaped flooded refrigerant evaporating section for cooling the lowerportion of another side wall and the remaining portion of the bottomwall, two spaced apart refrigerant manifolds one in communication withsaid non-flooded refrigerant section and the other in communication withsaid flooded section and injecting means directly connecting saidmanifolds for conducting refrigerant from said non-flooded section tosaid flooded section.

LAWRENCE A. PEELIPP.

